Conventionally, dedicated hardware has been used for communication equipment such as a router, a gateway, etc. In recent years, a network functions virtualization (NFV) has been put to practical use by which a function (hereinafter, referred to as a network service function) relating to a network service of various pieces of communication equipment has been virtualized as software on a general-purpose server.
When a virtual network function is requested, a technique is known by which a device simultaneously arranges the virtual network function on a server and sets a path for a network that connects to an arrangement destination server (see, for example, International Publication Pamphlet No. WO2015-118874)
When a packet goes through a plurality of virtual network functions (VNF) of a virtualized network, the packet is subjected to predetermined processing using each VNF. Furthermore, a transfer path of the packet may be dynamically changed. The transfer path of the packet is referred to as a service chain.
Unfortunately, when the service chain is implemented across sub-domains, a service index indicating the VNFs of a plurality of sub-domains is affected along with a setting change in the service chain, and therefore resetting of the plurality of sub-domains is needed and an operational efficiency is reduced.
Furthermore, a hierarchical service chain is proposed in which a service chain (high-order) that connects sub-domains and a service chain (low-order) that exists in the sub-domain are defined, respectively, and the service chains are hierarchically configured.
In the hierarchical service chain, processing is performed in which a high-order service chain is converted into a low-order service chain at an entrance of the sub-domain and the low-order service chain is converted into the high-order service chain at an exit of the sub-domain. Therefore, there is a problem in which, in the hierarchical service chain, the processing of the service chain becomes complicated.
Furthermore, documents such as Japanese Laid-open Patent Publication Nos. 2015-154421, 2015-154325, etc. are well known.